BY ERIC BELLMAN AND EDHI PRANASIDHI

JAKARTA, Indonesia—The largest investors in Bumi PLC called for the removal of Co-Chairman Nat Rothschild and a shake-up of the coal company's board, with an eye toward expanding operations and reducing debt.

The surprise move came just a few months after Mr. Rothschild called on the managers of some of Bumi's assets—which include some of the most important coal mines in the world—to improve their corporate governance.

Indonesia's powerful Bakrie family and domestic mining mogul Samin Tan—who jointly control just under 30% of Bumi's voting rights and around 47% of its total shares—last week called for a shareholders' meeting to ...